Datasheet

DRAFT
SAM3X / SAM3A [DATASHEET]
Atmel-11057C-ATARM-SAM3X-SAM3A-Datasheet_23-Mar-15
1432
45.10.9 Two-wire Serial Interface Characteristics
Table 45-61 describes the requirements for devices connected to the Two-wire Serial Bus. For timing symbols
refer to Figure 45-40.
Note: 1. Required only for f
TWCK
> 100 kHz
2. C
b
= capacitance of one bus line in pF. Per I2C Standard compatibility, C
b
Max = 400 pF
3. The TWCK low period is defined as follows: t
LOW
= ((CLDIV × 2
CKDIV
) + 4) × t
MCK
4. The TWCK high period is defined as follows: t
HIGH
= ((CHDIV × 2
CKDIV
) + 4) × t
MCK
5. t
CPMCK
= MCK bus period
Table 45-61. Two-wire Serial Bus Requirements
Symbol Parameter Conditions Min Max Unit
V
IL
Input Low-voltage -0.3 0.3 × V
DDIO
V
V
IH
Input High-voltage 0.7 × V
DDIO
V
CC
+ 0.3 V
V
hys
Hysteresis of Schmitt Trigger Inputs 0.150 – V
V
OL
Output Low-voltage 3 mA sink current – 0.4 V
t
r
Rise Time for both TWD and TWCK 20 + 0.1C
b
(1)(2)
300 ns
t
fo
Output Fall Time from V
IHmin
to V
ILmax
10 pF < C
b
< 400 pF
Figure 45-40
20 + 0.1C
b
(1)(2)
250 ns
C
i
(1)
Capacitance for each I/O pin – 10 pF
f
TWCK
TWCK Clock Frequency 0 400 kHz
Rp Value of Pull-up resistor
f
TWCK
≤ 100 kHz
(V
DDIO
- 0.4V) ÷ 3mA
1000ns ÷ C
b
Ω
f
TWCK
> 100 kHz 300ns ÷ C
b
t
LOW
Low Period of the TWCK clock
f
TWCK
≤ 100 kHz
(3)
–µs
f
TWCK
> 100 kHz
(3)
–µs
t
HIGH
High period of the TWCK clock
f
TWCK
≤ 100 kHz
(4)
–µs
f
TWCK
> 100 kHz
(4)
–µs
t
h(start)
Hold Time (repeated) START Condition
f
TWCK
≤ 100 kHz t
HIGH
–µs
f
TWCK
> 100 kHz t
HIGH
–µs
t
su(start)
Setup time for a repeated START condition
f
TWCK
≤ 100 kHz t
HIGH
–µs
f
TWCK
> 100 kHz t
HIGH
–µs
t
h(data)
Data hold time
f
TWCK
≤ 100 kHz 0 3 × t
CPMCK
(5)
µs
f
TWCK
> 100 kHz 0 3 × t
CPMCK
(5)
µs
t
su(data)
Data setup time
f
TWCK
≤ 100 kHz t
LOW
- 3 × t
CPMCK
(5)
–ns
f
TWCK
> 100 kHz t
LOW
- 3 × t
CPMCK
(5)
–ns
t
su(stop)
Setup time for STOP condition
f
TWCK
≤ 100 kHz t
HIGH
–µs
f
TWCK
> 100 kHz t
HIGH
–µs
t
BUF
Bus free time between a STOP and START
condition
f
TWCK
≤ 100 kHz t
LOW
–µs
f
TWCK
> 100 kHz t
LOW
–µs